Effect of forging ratio on the microstructure, mechanical properties and abrasive wear behavior of a new C–Cr–Mo–V martensitic steel

Abstract

C–Cr–Mo–V martensitic steel possesses high hardness, toughness and wear resistance, which benefits from the coordination of tempered martensite and alloy carbide in its microstructure. The size, content and distribution of alloy carbide have a great influence on the properties of steel. In this paper, the carbide characteristics and matrix microstructure of experimental steel were adjusted by controlling forging ratio. The results show that with the increase of forging ratio, the primary carbides distribute more homogeneously in the matrix and the amount of secondary carbides increases gradually, which enhances the pinning effect on grain boundary and refines the prior austenite grain. The hardness and impact toughness increase simultaneously with the increase of forging ratio, which benefits from the refinement of carbide and prior austenite grain. The increase of forging ratio not only promotes the refinement and dissolution of primary carbides, but also contributes the precipitation of secondary carbides. Therefore, the influence of forging ratio on the wear resistance is more complex. When the forging ratio reachs 6 or12, the wear resistance of experimental steel is enhanced which benefits from the higher content and finer size of primary carbides under small forging ratio, and the refinement of martensite matrix, uniform distribution of primary carbides and precipitation of secondary carbides under large forging ratio.